Tea in all its forms remains Britain’s favourite drink. While we enjoy it, it is also great news for our wellbeing and published evidence continues to show the many health benefits packed into a cup of tea. The following news round up from the Tea Advisory panel (TAP) takes a look at the latest, emerging evidence.
Blood glucose control following a meal (post-prandial) is important for the prevention of diabetes. New research shows black tea consumption may improve blood glucose control.1 Commenting on the research, Dr Tim Bond an advisor to www.teaadvisorypanel.com (TAP) notes: “This new study looked at the effect of black tea consumption on post-prandial blood glucose and insulin response following sugar consumption in normal and pre-diabetic subjects.2 In summary, the resulting data revealed that black tea consumption may improve blood glucose control following a meal. This may be due to black tea’s major bioactive compounds, the polyphenols.1
“The study was a randomized, double-blind, placebo-controlled crossover study. Twenty-four men and women aged 20-60 years, normal and pre-diabetic, randomly drank a sugar solution with a low dose of black tea polymerized polyphenol (BTPP), a high dose or a placebo drink.”
Dr Tim Bond adds: “The drink containing both low dose and high dose BTPP significantly decreased blood glucose increase after sugar intake compared with placebo in both the normal and pre-diabetic subjects.” In summary, Dr Tim Bond notes: “This reduction in postprandial blood glucose after black tea was consumed with a sugar solution suggests that it is the polyphenols in black tea that are linked with this benefit. A 2016 meta-analysis of 10 studies found that tea or tea extract could help to maintain a stable fasting blood insulin level and reduce waist circumference in people with type 2 diabetes mellitus.3”
Green tea intake has been associated with reduced risk of several types of cancer.4 Commenting on the research, Dr Catherine Hood an advisor to www.teaadvisorypanel.com (TAP) notes: “A new prospective study from Japan suggests that green tea may be associated with reduced risk of prostate cancer.5 The incidence of prostate cancer is much lower in Asia than in Western populations and green tea may be one of the lifestyle factors that influences risk.
“Using data from the Japan Public Health Center-based Prospective Study, this new research evaluated various lifestyle risk factors for prostate cancer among Japanese men. The results show that isoflavones and green tea intake in the typical Japanese diet may decrease the risk of localized and advanced prostate cancers and that abstinence from alcohol and tobacco might also be important factors in the prevention of advanced prostate cancer.“
Dr Tim Bond adds: “A possible link between green tea and bladder cancer has been investigated in a recent meta-analysis.6 A total of 25 case-control studies (15 643 cases and 30 795 controls) and seven prospective cohort studies (1807 cases and 443 076 participants) were included in the analysis. The meta-analysis showed that tea consumption was not significantly associated with bladder cancer risk. Risk was lower in the highest vs lowest category of tea consumption but the finding was not statistically significant. Specific analysis for black tea, green tea, and mate yielded similar results.”
In summary Dr Tim Bond notes: “Tea is the second most commonly consumed beverage in the world after water. As a result, these latest study findings together with many other published studies continue to suggest that Britain’s’ favorite beverage is good for our health including our bones, heart, vascular system and skin to name just a few health and wellbeing benefits, whatever your age.”
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The Tea Advisory Panel: The Tea Advisory Panel is supported by an unrestricted educational grant from the UK TEA & INFUSIONS ASSOCIATION, the trade association for the UK tea industry. The Panel has been created to provide media with impartial information regarding the health benefits of tea. Panel members include nutritionists; dieticians and doctors.
1 Kim Y, Keogh JB, Clifton PM. Polyphenols and Glycemic Control. Nutrients 2016;8(1).
2 Butacnum A, Chongsuwat R, Bumrungpert A. Black tea consumption improves postprandial glycemic control in normal and pre-diabetic subjects: a randomized, double-blind, placebo-controlled crossover study. Asia Pacific journal of clinical nutrition 2017;26(1):59-64.
3 Li Y, Wang C, Huai Q, et al. Effects of tea or tea extract on metabolic profiles in patients with type 2 diabetes mellitus: a meta-analysis of ten randomized controlled trials. Diabetes/metabolism research and reviews 2016;32(1):2-10.
4 Hayakawa S, Saito K, Miyoshi N, et al. Anti-Cancer Effects of Green Tea by Either Anti- or Pro- Oxidative Mechanisms. Asian Pacific journal of cancer prevention : APJCP 2016;17(4):1649-54.
5 Sawada N. Risk and preventive factors for prostate cancer in Japan: The Japan Public Health Center-based prospective (JPHC) study. Journal of epidemiology 2017;27(1):2-7.
6 Weng H, Zeng XT, Li S, et al. Tea Consumption and Risk of Bladder Cancer: A Dose- Response Meta-Analysis. Frontiers in physiology 2016;7:693.
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